In cold climates, the formation of ice on surfaces such as roadways, sidewalks and the like is a significant hazard to motorists and pedestrians. To prevent the formation of ice, or to melt ice that has already formed, it is common practice to spread a deicing composition on the surface. Deicing composition generally work by lowering the freezing point of water to below the ambient air temperature. Therefore, efforts are generally directed to developing compositions that lower the freezing point of water to a greater extent and/or are active over longer periods of time. There have been a wide variety of such compositions developed in the past, many of which are based on some combination of glycerol (also known as glycerin) and a salt, for example sodium chloride or calcium chloride, (see, for example, CA 2,640,852, DE 2127680, DE 2127679, CA 2,774,430, U.S. Pat. Nos. 8,182,714, 9,458,368 and DE 4,129,073).
While progress has been made, existing compositions comprising glycerol and a salt generally lack sufficient flowability making them more difficult to handle and spread on a surface. Such existing compositions are typically prepared by blending salt and glycerol in a mixer, thereby coating the surface of salt particles with glycerol, resulting in a material that becomes difficult to handle, especially when higher amounts of glycerol are used. Further, these compositions, as well as simple deicing compositions based solely on particulate salts, are not long lasting due to too rapid dissolution in the water the compositions create when melting the ice, thereby requiring frequent re-application of the deicing composition to the surface. Finally, many deicing compositions generally do not provide ice melting ability at very low temperatures.
A need remains for a deicing composition that is readily spreadable, longer lasting and/or is effective at very low temperatures.